With the popularization of high-quality digital cameras, smart mobile devices with high-resolution cameras, as well as user-friendly imaging and social networking applications, taking pictures, then editing and sharing, have become part of everyday life for many. Picture-related applications are extremely popular because pictures present attractive and vivid information. Nowadays, people record everyday life, communicate with each other and enjoy entertainment using various interesting imaging applications allowing original images to be transformed into processed images. The success of digital imaging applications is also due to the development of effective standards such as JPEG (Joint Photographic Experts Group) and JPEG 2000. JPEG is one of the early standards and is the most popular compression format to store or transmit images thanks to its efficiency and low complexity. JPEG 2000 is a more recent standard for still image coding, offering efficient image compression, progressive transmission, seamless scalability, region-of-interest coding and error resilience. However, even though JPEG 2000 outperforms JPEG in terms of compression efficiency, JPEG has remained the most popular format in a large variety of consumer imaging applications. Another popular format in addition to the above is PNG (Portable Network Graphics), which offers in addition a possibility of lossless and transparency (alpha channel) coding.
JPEG also offers a solution for tagging images. JPEG/Exif (Exchangeable image file format) is a popular way for digital cameras and other photographic capture devices to tag capture and location related metadata about photos. JPEG/JFIF (JPEG File Interchange Format) is the most popular format for storage and transmission of images on the World Wide Web. The two formats are often not distinguished from each other and are simply referred to as JPEG, each with its own application segments (APP0 for JFIF, APP1 for Exif) in the header of a JPEG file. Recently, a new standardization activity called JPEG XT has been initiated, addressing the needs of photographers for higher dynamic range (HDR) images in both lossy and lossless coding while retaining backward compatibility to the established legacy JPEG decoders. The central idea underlying the backward compatible coding of HDR content is to encode a low dynamic range version of the HDR image generated by a tone-mapping operator using a conventional JPEG encoder and to insert the extra encoded information for HDR in an application marker of a JPEG file header. Adopting this idea, any useful information can be embedded in the application markers of a JPEG file.
In many situations, a modified or processed image or media data element needs to be recovered to its original content. The typical solution is to keep both the original and the modified versions of the data element. This leads to increased bandwidth usage and storage resources. Thus, it becomes clear that this solution is not optimal, and there is a need for a more efficient solution allowing the original media content to be recovered.
It is an object of the present invention to overcome the problem related to recovering the original media content once the original media data element has been modified.